Default Rooted Nexus 5 out of box, recently updated 4.4.2 OTA and now root is gone

When I open up superSU, it says:

There is no SU binary installed, and super SU cannot install it.
If you just upgraded to android 4.3, you need to manually re-root.

If I turn the Nexus on in recovery mode, it still says it's unlocked.
So at this point, is there anything I can do to restore root status without factory resetting? I made a backup with titanium backup but it was a while ago so I would rather not use it if there is another way.
I've read somewhere that rooting it should mean OTA updates should no longer work but somehow, it still went through and I updated it without thinking too much.